HU214141B - Process for preparing of water treating agents containing n-substituted amino acid derivatives and process for water treating - Google Patents

Abstract

(57) EXTRACT The present invention relates to a process for the preparation of a water treatment agent containing a carboxy-methylated or main-stained methylated amino acid on a nitrate engine, in the form of an acid or a β-alanine a) in a mildly alkaline aqueous reaction mixture melted with 1 mol of chloroacetic acid to 1 mol of chloroacetic acid. or b) in an aqueous mixture, in the presence of an acid or Lewis acid, 1 mol of the amino acid, reacted with 1 to 1.5 molar main acid, then with 1 to 2.5 mol of main maldehyde or main maldehyde, and if the reaction is carried out in the presence of hydrochloric acid, excess thereof is eliminated. and, if desired, the reaction mixture obtained by a) or b) is supplemented with bleaching water treatment additive and / or excipients. The present invention further relates to a method of treating water with an agent prepared as described above. ŕ

Description

The present invention relates to a process for the preparation of water treatment agents containing carboxymethylated or phosphonomethylated amino acids by means of a natural amino acid or B-alanine.

(a) in a slightly basic aqueous reaction mixture, reacted with 1 to 1.2 moles of chloroacetic acid per mole of amino acid, or

Scope of the description: 5 pages

(b) in an aqueous mixture, in the presence of an acid or Lewis acid, reacting with 1 to 1.5 moles of phosphoric acid per mole of amino acid, followed by 1 to 2.5 moles of formaldehyde or formaldehyde source and removing the excess from the reaction mixture; optionally supplementing the reaction mixture obtained by process a) or b) with customary water treatment additives and / or auxiliaries.

The present invention also relates to a process for treating water with an agent as described above.

HU 214 141 Β

The present invention relates to a process for the preparation of water treatment agents containing N-substituted amino acid derivatives. The invention further relates to a process for treating water, in particular for the purpose of inhibiting corrosion and limescale.

In developed industrial countries, more than 4% of gross national income is consumed by direct and indirect damage caused by corrosion. The direct damage caused by corrosion can be very different, depending on the various forms of corrosion. Indirect damages, eg. loss of production, loss of efficiency, repair and maintenance costs of industrial equipment, machinery, vehicles, corrosion protection, in most cases outweigh direct damage. When designing corrosion protection systems, it is possible to design non-resistant materials with additional protection from the selection of corrosion-resistant structural material through non-resistant but regularly renewed structures. The latter is achieved by the inhibitory treatment of industrial cooling water systems.

The construction materials for refrigeration systems and other industrial equipment for water flow or water storage are most often low alloy or non alloy steels, in addition galvanized steel, aluminum, copper, alloy steels and occasionally lead. Changes caused by cooling water appear on structural materials primarily in the form of corrosion, deposition and microbiological contamination. These processes reduce cooling efficiency, increase maintenance and maintenance costs.

The structural materials used determine the compounds that can be used to control degradation.

The most commonly used chemicals to suppress corrosion of mild and carbon steels or cast iron parts in neutral media used to be polyphosphates, tannin and vanadates; later the use of phosphonic and carboxyphosphonic acids became widespread. Phosphonic acids are used in a number of industries (such as oil, paper, textiles, and paints) primarily to prevent scale and corrosion, but they can also be used as solutions in metals and as dispersants. The active ingredients of some known phosphonic acid water treatment agents are listed in Table 1.

Table 1

Patent Number Materials Used

US 3,890,228

US 4 105 587

US 4,163,733

US 4,206,075

US 4,209,391

-Hydroxyethane-1,1-diphosphonic acid and methacrylate polymer Phosphonates with phosphates and maleic acid Dimethylaminomethanediphosphonic acid with polymeric carboxylic acids or their methyl esters, phosphoric acid and zinc salts Nitrilotriethylphosphonic acid 1,1-Diphosphonic acid with polyphosphates Phosphonic acid with phosphoric acid, a polymer based on methacrylic acid and salts of divalent metals

Patent number Applied materials US 4,209,398 5 Polymeric carboxylic or polycarboxylic acids with phosphonic acid or with phosphoric acid or their salts

Table 2 summarizes the protective effects of certain representative methylamine phosphonic acids widely used as corrosion inhibitors.

Table 2

Phosphonic acid Protective effect on carbon steel%

Nitro-tri (methylene-phosphonic acid) N (CH ₂ -PO ₃ H ₂ ) ₃ 53.3

Ethylenediaminetetra (methylene phosphonic acid) (H ₂ O ₃ P-CH ₂ ) ₂ N- (CH 2) 2 -N (CH ₂ -PO ₃ H ₂ ) ₂ 63.3

Diethylenetriaminepenta (methylene phosphonic acid) (H ₂ O ₃ P-CH ₂ ) ₂ N- (CH ₂ ) -N (CH ₂ -PO ₃ H) -CH ₂ -N (CH ₂ -PO ₃ H) ₂ 74.2

Hexamethylenediaminetetra (methylene phosphonic acid) (H ₂ O ₃ P-CH ₂ ) ₂ N - (CH ₂ ) ₆ -N (CH ₂ -PO ₃ H ₂ ) ₂ 90.0

One of the important goals of modem environmental protection is to keep the amount of phosphorus released into nature as low as possible in order to reduce the eutrophication of natural waters. Therefore, the otherwise highly effective phosphonic acid corrosion inhibitors enumerated in the prior art 30 are sought to be replaced by substances which do not, or significantly less, release phosphorus into the environment.

In view of the above, amino acids substituted on the nitrogen atom with carboxymethyl or phosphonomethyl groups were prepared and tested for their corrosion inhibiting activity (Magyar Kémiai Folyóirat 97, 119 (1991)). It has been found that although the moderate corrosion inhibitory effect of the parent amino acids can be enhanced by both carboxymethylation and phosphonomethylation, the corrosion inhibitory activity of the resulting compounds remains moderate.

Continuing our investigations, it has been surprisingly discovered that the reaction mixtures of N-carboxymethyl and N45-phosphonomethyl amino acids have a significantly better corrosion inhibition effect than the pure N-substituted amino acids isolated from them.

Analyzing the formation reaction mixtures of N-carboxymethyl and N-phosphonomethyl amino acids by thin layer chromatography, it was found that besides the target compound (typically 60-95% yield), disubstituted by-products were also typically formed 2. With a yield of -10%, and about 2-25% of the starting amino acid remains unreacted in the mixture. Considering that the anticorrosive activity of the starting amino acid was always found to be less than that of the corresponding N-carboxymethylated or

N-phosphonomethylated derivative, the formation reaction2

As a result of the increased corrosion inhibitory effect of the mixture, we could not have expected, but the effect would have been expected to decrease.

This discovery enables us to produce high-performance water treatment agents in a very simple, simple manner, thus saving on the cost and cost of isolating the active ingredients.

The present invention relates to a process for the preparation of water treating agents containing carboxymethylated or phosphonomethylated amino acids on a nitrogen atom by the use of a natural amino acid or B-alanine.

(a) in a slightly basic aqueous reaction mixture, reacting with 1 to 1.2 moles of chloroacetic acid per mole of amino acid, or

b) in an aqueous mixture, in the presence of an acid or Lewis acid, reacting with 1 to 1.5 moles of phosphoric acid per mole of amino acid, followed by 1 to 2.5 moles of formaldehyde or formaldehyde source and removing the excess from the reaction mixture.

The resulting reaction mixture may be added directly to the water in the equipment to be protected for corrosion and limescale inhibition. However, if desired, other customary water-treating additives may be added to the reaction mixture to widen the effect or to obtain additional beneficial effects (e.g., biocidal effect). Examples of such additives include various polymers and copolymers, inorganic phosphates, inorganic polyphosphates, metal salts, alkanolamines and the like; detailed guidance on additives and their amounts to be used is provided in the literature, including the patents cited above. Specific types of additives include known corrosion inhibitors and anti-limescale agents that enhance the corrosion and / or limescale effect. The invention thus also relates to a process for combining the reaction mixture obtained above with one or more other known water treatment additives and / or auxiliaries.

In the above process (a) (i.e., carboxymethylation), sodium hydroxide is preferably used to basify the reaction mixture. Preferably, the solution of the amino acid in 1N aqueous sodium hydroxide solution is mixed with a solution of chloroacetic acid in aqueous sodium hydroxide, heated to 90-110 ° C, and the reaction is carried out at this temperature while the pH is of sodium hydroxide solution is maintained between 10 and 11. After the addition of sufficient amount of sodium hydroxide to neutralize the hydrochloric acid liberated during the reaction, the mixture was heated at 90-100 ° C for a further 0.5-2 hours.

In process b) above, any acid, including Lewis acids, can be used. Examples of Lewis acids are aluminum, zinc, cobalt and molybdenum salts and oxides, as well as vanadates. As the acid, for example, hydrochloric acid, maleic acid or hydroxyethanediphosphonic acid can be used. These materials are used in an amount sufficient to block at least one solitary electron pair on the amino group or amino groups of the parent amino acid. A very suitable acid from a technological point of view is hydrochloric acid, which develops spontaneously when the phosphoric acid reagent is formed from phosphorus trichloride and water. The reaction mixture thus formed, containing phosphoric acid and hydrochloric acid, can be directly added to the amino acid. The reaction mixture is then heated and the formaldehyde or formaldehyde source (preferably paraformaldehyde or other formaldehyde polymer) is added and the reaction is carried out at 90-105 ° C. If the reaction is carried out in the presence of hydrochloric acid, after the reaction, excess hydrochloric acid must be removed from the reaction mixture. The simplest way is to purge the reaction mixture with water vapor.

The invention further relates to a process for treating water, in particular for corrosion and limescale inhibition, by adding to the water to be treated the water treatment agent prepared as described above in an amount of 5-100 mg dry matter per liter of water. By "dry matter" is meant water components other than water.

Further details of the invention are set forth in the Examples

Example 11

Preparation of water treatment agents containing N- (Carboxymethyl) amino acids

26.7 g (0.3 mol) of β-alanine were dissolved in 300 ml of 1 N aqueous sodium hydroxide solution. A solution of chloroacetic acid (28.4 g, 0.3 mol) in 1N aqueous sodium hydroxide solution (300 ml) was added and the resulting mixture was heated to 100-110 ° C. The hydrochloric acid formed during the reaction was neutralized by the continuous addition of 1 N aqueous sodium hydroxide solution. After addition of 300 ml of alkali to neutralize the calculated amount of hydrochloric acid (6-8 hours), the mixture was stirred for 1 hour. A mixture of N-carboxymethyl-B-alanine (42.5 g) was obtained, which was subjected to TLC analysis (adsorbent: Kieselgel, eluent: 5: 1 water / methanol or 4: 1: 1 water / benzene). methanol mixture), with about 6% unconverted B-alanine, also containing by-products (most likely N, N-di-carboxymethyl) in about 6% yield.

For analysis, the solvent was removed from a small sample of the reaction mixture on a rotary evaporator, the residue dissolved in a little water, passed through a cation exchange column, the aqueous solution was evaporated and the residue was recrystallized from water. Analysis for this pure N-carboxymethyl-B-alanine (C5H9NO4, M = 147): Calculated: C, 40.82%, H, 6.12%, N, 9.52%. % C: 40.56%, H: 6.23%, N: 9.32%.

By the above procedure, 0.3 moles of the appropriate amino acid were used as photoproducts

N- (carboxymethyl) aspartic,

N- (carboxymethyl) glycine,

N- (carboxymethyl) glutamic acid,

N- (carboxymethyl) -phenylalanine

N-carboxymethylvaline; and

Reactions containing N-carboxyethyl norvaline were also prepared. If starting material is aspartic acid or glutamic acid (two

The amino acids containing carboxyl groups) were used and dissolved in 600 ml of 1N aqueous sodium hydroxide solution. For comparative purposes, the pure main product was also isolated from a small sample of each reaction mixture obtained.

Example 2

Preparation of Water Treatment Agents Containing N-Phosphonomethyl Amino Acids (A) 49.5 g of glutamic acid were mixed with 24 ml of water, 30 ml of concentrated hydrochloric acid and 33 g of phosphoric acid, and 12 g of paraformaldehyde was added while heating to 70-80 ° C. at a rate such that depolymerization of paraformaldehyde occurs, but formaldehyde cannot escape from the system. After the addition of paraformaldehyde, the mixture was gradually heated to 100 ° C and maintained at this temperature for 1 hour. The excess hydrochloric acid was then removed by evaporation of water vapor. When the water vapor distillate reached a pH of 4 to 5, the water vapor flow was stopped.

A small portion of the reaction mixture thus obtained was isolated by preparative thin layer chromatography (adsorbent: gypsum-free Kieselgel, eluent: water: benzene: methanol = 2: 1: 1, v / v) to give N-phosphonomethylglutamic acid as the main product. In addition to the main product, the reaction mixture also contained N, N-di (phosphonomethyl) glutamic acid in a yield of about 4%; 15% of the starting glutamic acid remained unreacted.

(B) The procedure described in (A) was repeated except that an equivalent amount of aspartic acid was used instead of glutamic acid. From the reaction mixture, a sample of pure N-phosphonomethyl-aspartic acid was isolated for analysis.

(C) The procedure of (A) was repeated except that 6.0 g of ZnO was added to the reaction mixture instead of concentrated hydrochloric acid and the water vapor purge was omitted. The amount of unreacted glutamic acid increased to 22%, thereby reducing proportionally the amount of the main N-phosphonomethylglutamic acid product and the N, N-di-phosphonomethylglutamic acid by-product.

(D) 16.5 g of phenylalanine were mixed with 70 ml of water, 90 ml of concentrated hydrochloric acid and 8.4 g of phosphoric acid, and 4 g of paraformaldehyde was added to the mixture at 70-80 ° C at a rate such that depolymerization of paraformaldehyde but the formaldehyde should not leave the system. After the addition of paraformaldehyde, the mixture was gradually heated to 100 ° C and maintained at this temperature for 3 hours. The excess hydrochloric acid was then removed by evaporation of water vapor. Water vapor permeability was terminated when the pH of the water vapor distillate was between 4 and 5.

For the purpose of comparative analysis, the main product, N-phosphonomethylphenylalanine, identified by elemental analysis, was isolated from the resulting reaction mixture as described in (A). In addition to the main product, the reaction mixture also contained N, N-di (phosphonomethyl) phenylalanine in about 10% yield; 20% of the starting phenylalanine remained unreacted.

(E) The procedure described in (D), except that 36.0 g of MoO ₃ by weight, we used an equivalent amount of 37% aqueous formaldehyde solution in place of paraformaldehyde in place of hydrochloric acid.

The water vapor flow was omitted. The amount of unreacted phenylalanine increased to 30%, with a corresponding decrease in the amount of the main product and the by-product.

Examination of the corrosion inhibiting effect

The tests were performed on Al 1 carbon steel specimens. The specimens were deoxidized by glass-blast surface cleaning prior to corrosion, degreased with acetone, and weighed to the nearest 1 mg after drying. Corrosion medium CaSO4.2H ₂ O 97.68 mg, 25.26 mg of CaCl ₂ .2H ₂ O, 46.50 mg of MgSO ₄ .2H ₂ O and 22.50 mg of aqueous solution containing NaHCO> 3 was used per liter, which To 1 liter of the inhibition assay, 50 mg of the test compound and 50 mg of the test compound were added in an appropriate amount. Prior to the test, the pH of the corrosive solutions was adjusted to 7 with sodium hydroxide. The specimens were maintained for 72 hours in a corrosion medium heated to 40 ± 2 ° C. The corrosion products were then removed from the specimens by treatment with inhibitor-containing hydrochloric acid. The clean metal surface was rinsed thoroughly with water, dried after immersion in acetone, and weighed to the nearest 1 mg. The corrosion inhibition efficiency (η,%) was calculated from the formula (m _o - mj) -100 m _o , where 1¾ is the weight loss of the specimen immersed in the corrosion medium containing the inhibitor.

The results are summarized in Table 3.

Table 3

Results of corrosion tests

Corrosion Inhibitory Effectiveness,% Test compound alone in its Formulation

N- (carboxymethyl) glycine 38.6 48.3 N- (carboxymethyl) -B-alanine 32.0 48.3 N- (carboxymethyl) -phenylalanine -15.7 37.5 N- (carboxymethyl) glutamic acid 46.0 52.1 N- (carboxymethyl) -valine 7.7 63.5 N- (carboxymethyl) norvaline -13.6 22.2 N- (phosphonomethyl) phenylalanine 59.1 78.3 N- (phosphonomethyl) glutamic acid 52.0 58.4 N- (phosphono-methyl) -aspartic 51.2 62.3

From the data in the table it can be seen that the corrosion inhibiting effect of each of the tested compounds is significantly increased when used as their reaction mixtures. Particularly striking is the increase in the reaction mixtures containing N-carboxymethylphenylalanine and N-carboxymethylnorvaline, where the main product is not only corrosive but corrosive, and

EN 214 141 Β in the presence of a small amount of by-product.

Examination of the antifouling effect:

The following water treatment agent samples were tested for antifouling activity:

Sample A: The reaction mixture prepared according to Example 1 containing N-carboxymethyl-B-alanine was treated with 40 g of polyacrylate having an average molecular weight of 1500, 10 g of hexametaphosphate and 5 g of nitrilotrimethylene phosphonic acid.

Sample B: Reaction mixture prepared according to Example 1 containing N-carboxymethyl-aspartic acid.

Sample C: A reaction mixture of N-carboxymethyl-aspartic acid prepared in Example 1 to which was added 55 g of polyacrylate having an average molecular weight of 1500, 10 g of hexametaphosphate and 5 g of hydroxyethane diphosphonic acid.

Sample D: Reaction mixture of Example 1 containing N-carboxymethylglutamic acid.

Sample E: A reaction mixture of N-carboxymethyl-glutamic acid prepared as in Example 1 to which was added 55 g of polyacrylate having an average molecular weight of 1500, 10 g of hexamethaphosphate and 5 g of hydroxyethanediphosphonic acid.

To 250 ml of 0.02 M aqueous calcium chloride solution was added a sample of A-E corresponding to 0.5 mg of dry matter. To the resulting mixture was added 250 mL of a 0.04M aqueous sodium bicarbonate solution. The mixture was mixed and a sample was taken and the Ca ²⁺ content of the sample at time 0 was determined by titration with EDTA solution with murexide indicator. The mixture was then heated at 60 ° C for the period indicated in Table 4, and the precipitated CaCO ₃ was filtered off from the mixture and titrated to determine the Ca ²⁺ content of the filtrate at time "t". The same measurements were performed on a solution without inhibitor (blank). From the data obtained, the% efficiency was calculated using the following formula:

[F (i, t) -F (v, t)] - 100

F (v, 0) -F (v, t) where

F (i, t) is the Ca ²⁺ content of the filtrate of the inhibitor-containing mixture at time t,

F (v, t) is the Ca ²⁺ content of the blank of the blank at time 'f', F (v, 0) the Ca ²⁺ content of the starting mixture.

The results are shown in Table 4.

Table 4

Antifouling effect,%

Sample mark after 2 hours after 4 hours after 24 hours

"THE" 82.1 79.2 70.4 "B" 67.2 66.2 57.5 "C" 85.1 78.5 69.3 "D" 65.5 55.8 44.2 "E" 91.2 88.5 77.7 PATENT CLAIMS

CLAIMS 1. A process for being carboxymethylated on a nitrogen atom

Claims (4)

CLAIMS 1. A process for the preparation of water treatment agents containing carboxymethylated or phosphonomethylated amino acids on a nitrogen atom, characterized in that the amino acid or β-alanine is a natural amino acid. (a) in a slightly basic aqueous reaction mixture, reacting with 1 to 1.2 moles of chloroacetic acid per mole of amino acid, or b) in an aqueous mixture, in the presence of an acid or Lewis acid, reacting with 1 to 1.5 moles of phosphorous acid per mole of amino acid, followed by 1 to 2.5 moles of formaldehyde or formaldehyde source and removing the excess from the reaction mixture in the presence of hydrochloric acid; and optionally adding a conventional water-treating additive and / or auxiliary agent to the reaction mixture obtained by process a) or b) above. (Priority: March 11, 1997) Process according to claim 1, characterized in that it is based on β-alanine, glycine, aspartic acid, glutamic acid, phenylalanine, lysine or histidine. (Priority: December 13, 1993) A process for treating water, in particular for corrosion and limescale inhibition, comprising adding to the water to be treated the water treatment agent according to claim 1 in an amount of 5-100 mg of dry matter per liter. (Priority: March 11, 1997) The process according to claim 3, wherein the water treatment agent according to claim 2 is added to the water to be treated in an amount of 20-100 mg dry matter / l. (Priority: December 13, 1993)